Single-cell analysis of peripheral blood from high-altitude pulmonary hypertension patients identifies a distinct monocyte phenotype

Immune and inflammatory responses have an important function in the pathophysiology of pulmonary hypertension (PH). However, little is known about the immune landscape in peripheral circulation in patients with high-altitude pulmonary hypertension (HAPH). We apply single-cell transcriptomics to characterize the monocytes that are significantly enriched in the peripheral blood mononuclear cells (PBMC) of HAPH patients. We discover an increase in C1 (non-classical) and C2 (intermediate) monocytes in PBMCs and a decrease in hypoxia-inducible transcription factor-1α (HIF-1α) in all monocyte subsets associated with HAPH. In addition, we demonstrate that similar immune adaptations may exist in HAPH and PH. Overall, we characterize an immune cell atlas of the peripheral blood in HAPH patients. Our data provide evidence that specific monocyte subsets and HIF-1α downregulation might be implicated in the pathogenesis of HAPH.

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The data supporting the findings from this study are available in the main manuscript and supplementary materials. The raw sequence data reported in this paper have been deposited in the GenomeSequence Archive of the Beijing Institute of Genomics (BIG) Data Center, BIG,Chinese Academy of Sciences (GSA-Human: RA002501) and are publicly accessible at https://ngdc.cncb.ac.cn/gsa-human/browse/HRA002501. Any other raw data or non-commercial material used in this study are available from the corresponding author upon request. Source data are provided with this paper.
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All experiments except for single cell sequencing and flow cytometry were done in replicate, and all attempts at replication were successful.
Animals were randomly separated to experimental and control groups. Random fields from each slide and random sections from mice were used to calculate the wall area/total vessel area for H&E staining. For other in vitro experiments, samples were randomly grouped into experimental groups and controls.
Animals phenotypes such as right heart catheterization and right heart hypertrophy index were determined in a blinded fashion. Blind method was also used for data collection and analysis involving flow cytometry, immunoblotting, real time PCR and cell viability determination.

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Jurkat Clone E6-1 T cells were purchased from Procell Life Science & Technology Co., Ltd. (Wuhan, China) and Human pulmonary artery smooth muscle cells (PASMCs) were purchased from ScienCell Research Laboratories.
Jurkat Clone E6-1 T was identified by Procell Life Science & Technology Co., Ltd. (Wuhan, China), and STR typing of cell line DNA showed that it completely matched the cell type in the cell bank, and no cross-contamination was found.
Jurkat Clone E6-1 T was identified by Procell Life Science & Technology Co., Ltd. (Wuhan, China), and mycoplasma contamination was not found.
No commonly misidentified cell lines were used.